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从锦屏二级水电站深埋隧洞施工中发现,结构面的剪切滑移可能诱发极强岩爆。为研究结构面对滑移型岩爆的控制机制,利用水泥砂浆作为模型材料,制作3种不同起伏高度的不规则锯齿形结构面,并进行直剪试验,研究不同起伏高度、剪切速率和法向压力下的结构面强度特征和破坏机制,并对现场的滑移型岩爆进行初步的机制分析。研究结果表明,每种起伏高度的结构面的峰值抗剪强度和残余强度均随法向压力增大而增大;随着起伏高度的增加,结构面的抗剪强度、内摩擦角逐渐增加;随着剪切速率增加,结构面抗剪强度具有先增加后减小的趋势;不同工况下结构面的破坏机制可归纳为锯齿的滑移错断机制、结构面上下盘的拉伸断裂机制和上盘前端下盘后端的冲击断裂机制;结构面的起伏高度越大、法向应力越高,冲击断裂的规模越大;现场结构面的应力集中程度、结构面面壁凸台的尺寸、强度和位置等决定了滑移型岩爆发生的等级、爆坑深度。
It is found from the deep-buried tunnel construction of Jinping II Hydropower Station that the shear slip of structural plane may induce strong rock burst. In order to study the control mechanism of the structure in the face of the sliding type rockburst, three kinds of irregular zigzag structures with different undulating heights were made by using cement mortar as the model material, and the direct shear tests were carried out to study the effects of different relief heights, shear rates and The structural surface strength characteristics and failure mechanism under the normal pressure and the initial mechanism analysis of on-site slipping rockburst. The results show that the peak shear strength and residual strength of the structural plane with each undulating height increase with the increase of normal pressure. With the increase of the undulating height, the shear strength and internal friction angle of the structural plane increase gradually. With the increase of shear rate, the shear strength of the structural plane firstly increases and then decreases. The failure mechanism of the structural plane under different conditions can be summarized as the sliding fault mechanism of serration, the tensile fracture mechanism of the upper and lower plate of the structural plane And the impact of the front end of the plate lower end of the disk breakage mechanism; the greater the undulating height of the structure surface, the higher the normal stress, the greater the impact of the fracture size; site structure of the surface stress concentration level, And location determine the level of slippery rockburst, depth of crater.